Glaucoma — MCQs

Glaucoma Indian Medical PG Practice Questions and MCQs

Question 201: Latanoprost is used in the treatment of which condition?

A. Induction of labor
B. Refraction
C. Glaucoma (Correct Answer)
D. Iridocyclitis

Explanation: **Explanation:** **Latanoprost** is a synthetic **Prostaglandin F2-alpha (PGF2α) analogue**. It is the first-line medical therapy for **Primary Open-Angle Glaucoma (POAG)** and Ocular Hypertension. **Why Glaucoma is correct:** Latanoprost works by increasing the **uveoscleral outflow** of aqueous humor (the unconventional pathway). By facilitating the drainage of fluid through the ciliary muscle into the suprachoroidal space, it effectively lowers Intraocular Pressure (IOP). It is preferred due to its once-daily dosing and superior efficacy compared to older drugs like Timolol. **Analysis of Incorrect Options:** * **A. Induction of labor:** While other prostaglandins like Dinoprostone (PGE2) and Misoprostol (PGE1) are used for cervical ripening and induction, Latanoprost is specifically formulated for ophthalmic use and has no role in obstetrics. * **B. Refraction:** Drugs used in refraction are cycloplegics (e.g., Atropine, Cyclopentolate) which paralyze the ciliary muscle to reveal the true refractive error. Latanoprost does not affect accommodation or pupil size significantly. * **C. Iridocyclitis:** This is an inflammatory condition (anterior uveitis). Treatment involves topical steroids and cycloplegics (to prevent synechiae). Prostaglandin analogues are actually **contraindicated** in active iridocyclitis as they are pro-inflammatory mediators. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Increases uveoscleral outflow (High yield). * **Side Effects:** Increased pigmentation of the iris (heterochromia), **hypertrichosis** (increased eyelash growth/thickness), and cystoid macular edema (CME). * **Storage:** Unopened bottles should be stored in a refrigerator (2-8°C). * **Other PGF2α analogues:** Bimatoprost, Travoprost, Tafluprost.

Question 202: Which of the following instruments is used as a self-tonometer?

A. Diaton palpebral tonometer
B. Rebound tonometer (Correct Answer)
C. Perkins tonometer
D. Dynamic contour tonometer

Explanation: **Explanation:** The **Rebound Tonometer** (e.g., Icare) is the correct answer because it is designed for ease of use without the need for topical anesthesia or a slit lamp. It works on the principle of **induction-deceleration**: a tiny, disposable motorized probe bounces off the cornea, and the device measures the deceleration of the probe to calculate Intraocular Pressure (IOP). Because it is portable, requires no drops, and is minimally invasive, it is the primary instrument used for **home monitoring (self-tonometry)** and in pediatric populations. **Analysis of Incorrect Options:** * **Diaton Palpebral Tonometer:** This measures IOP through the **eyelid** (transpalpebral). While it doesn't require anesthesia, it is technically difficult to self-administer accurately and is less reliable than rebound tonometry. * **Perkins Tonometer:** This is a **handheld version of the Goldmann Applanation Tonometer (GAT)**. While portable, it requires topical anesthesia (Proparacaine) and Fluorescein dye, making it unsuitable for self-use. It is ideal for bedridden or anesthetized patients. * **Dynamic Contour Tonometer (Pascal):** This uses a piezoelectric sensor to measure IOP and is unique because it is **independent of Central Corneal Thickness (CCT)**. However, it is a bulky, slit-lamp mounted device that cannot be used by a patient on themselves. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Goldmann Applanation Tonometry (GAT) remains the clinical gold standard. * **Imbert-Fick Law:** The principle behind applanation tonometry ($P = F/A$). * **Schiotz Tonometer:** An older, indentation tonometer that uses a conversion table; it is prone to errors based on **scleral rigidity**. * **Non-Contact Tonometer (Air-puff):** Commonly used for screening; it uses a puff of air to flatten the cornea.

Question 203: Treatment of malignant glaucoma may include all the following except?

A. Pilocarpine (Correct Answer)
B. Atropine
C. Vitrectomy
D. Laser iridotomy

Explanation: **Explanation:** **Malignant Glaucoma** (also known as Ciliary Block Glaucoma or Aqueous Misdirection Syndrome) is a rare but serious condition where aqueous humor is diverted posteriorly into the vitreous cavity. This increases vitreous volume, pushing the lens-iris diaphragm forward and causing a flat anterior chamber with high intraocular pressure. **Why Pilocarpine is the Correct Answer (The "Except"):** Pilocarpine is a miotic (parasympathomimetic) and is **contraindicated** in malignant glaucoma. It causes contraction of the ciliary muscle, which leads to further forward displacement of the lens-iris diaphragm and tightening of the ciliary ring. This exacerbates the posterior diversion of aqueous, worsening the condition. **Analysis of Other Options:** * **Atropine (Mydriatic-Cycloplegic):** This is the drug of choice. It relaxes the ciliary muscle, causing the lens-iris diaphragm to move posteriorly, thereby widening the ciliary ring and restoring normal aqueous flow. * **Laser Iridotomy:** While a patent iridotomy is often performed to rule out pupillary block glaucoma (the primary differential diagnosis), it is a standard step in the initial management protocol. * **Vitrectomy:** If medical and laser therapies fail, a pars plana vitrectomy is the definitive surgical treatment. It removes the vitreous "pocket" where aqueous is trapped, allowing the iris-lens diaphragm to fall back. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** Occurs typically after surgery for angle-closure glaucoma in eyes with shallow anterior chambers. * **Key Finding:** Axial shallowing of the anterior chamber (both central and peripheral). * **Medical Management Triad:** 1. **Cycloplegics:** Atropine 1% (to pull the lens back). 2. **Hyperosmotics:** Mannitol (to shrink the vitreous). 3. **Aqueous Suppressants:** Timolol or Acetazolamide. * **Laser Treatment:** Nd:YAG laser can be used for hyaloidotomy (disrupting the anterior hyaloid face).

Question 204: What is the normal range for intraocular pressure?

A. 7 - 14 mm Hg
B. 2.1 - 6 mm Hg
C. 10 - 21 mm Hg (Correct Answer)
D. 16 - 32 mm Hg

Explanation: **Explanation:** **1. Why Option C is Correct:** Intraocular pressure (IOP) is determined by the dynamic balance between the production of aqueous humor by the ciliary body and its drainage through the trabecular meshwork and uveoscleral pathways. In the general population, IOP follows a Gaussian (normal) distribution curve. The statistically defined normal range is **10 to 21 mm Hg**. This range represents the mean (approximately 15.5 mm Hg) plus or minus two standard deviations. **2. Why Other Options are Incorrect:** * **Option A (7 - 14 mm Hg):** This range is too low. While some individuals naturally have low IOP, setting the upper limit at 14 would misclassify a large portion of the healthy population as having ocular hypertension. * **Option B (2.1 - 6 mm Hg):** These values represent **Hypotony**. IOP below 5-6 mm Hg can lead to phthisis bulbi, macular edema, and corneal decompensation. * **Option D (16 - 32 mm Hg):** Values consistently above 21 mm Hg are classified as **Ocular Hypertension**. While not everyone with an IOP >21 mm Hg has glaucoma, they are at a significantly higher risk for optic nerve damage. **3. NEET-PG High-Yield Clinical Pearls:** * **Goldmann Applanation Tonometry (GAT):** The "Gold Standard" for measuring IOP. It is based on the **Imbert-Fick Law**. * **Diurnal Variation:** IOP is not constant; it is typically highest in the early morning. A variation of **3–6 mm Hg** is normal; >8 mm Hg is suggestive of glaucoma. * **Central Corneal Thickness (CCT):** A thin cornea leads to an underestimation of IOP, while a thick cornea leads to an overestimation. * **Glaucoma Definition:** Remember, glaucoma is a progressive optic neuropathy; it is **not** defined solely by high IOP, though IOP is the only modifiable risk factor.

Question 205: Which tonometer is used for the irregular surface of the cornea?

A. Mackey-Marg tonometer (Correct Answer)
B. Rebound tonometer
C. Dreger's tonometer
D. Maklakov tonometer

Explanation: The **Mackey-Marg tonometer** is the instrument of choice for measuring intraocular pressure (IOP) in eyes with **irregular, scarred, or edematous corneas**. ### Why Mackey-Marg is Correct The underlying principle is **Electronic Applanation**. Unlike the Goldmann Applanation Tonometer (GAT), which requires a perfectly smooth, thin, and regular corneal surface to create a precise meniscus, the Mackey-Marg uses a small central transducer (plunger) surrounded by a guard ring. The guard ring flattens the surrounding irregular cornea, while the central transducer measures the pressure. This design minimizes the errors caused by corneal surface irregularities, scarring, or the presence of a therapeutic bandage contact lens. ### Explanation of Incorrect Options * **Rebound Tonometer (e.g., Icare):** Uses a small disposable probe that bounces off the cornea. While it doesn't require anesthesia, it is sensitive to corneal thickness and is not specifically designed for highly irregular surfaces. * **Dreger’s Tonometer:** This is a handheld version of the Goldmann tonometer. It operates on the same principle as GAT and is therefore unsuitable for irregular corneas. * **Maklakov Tonometer:** An early form of applanation tonometry using a weighted metal cylinder. It is highly dependent on corneal curvature and surface integrity, making it inaccurate for irregular surfaces. ### NEET-PG High-Yield Pearls * **Goldmann Applanation Tonometry (GAT):** The current **Gold Standard** for IOP measurement. * **Pneumotonometry:** Another excellent option for irregular corneas or when a bandage contact lens is in situ. * **Tono-Pen:** A portable electronic tonometer based on the Mackey-Marg principle; it is the most commonly used clinical tool for scarred or irregular corneas today. * **Schiotz Tonometer:** An indentation tonometer; it is contraindicated in cases of corneal ulcers or suspected globe perforation.

Question 206: Coloured haloes are found in all except:

A. Pigmentary glaucoma
B. Acute-angle-closure glaucoma
C. Cataract
D. Uveitis (Correct Answer)

Explanation: **Explanation:** Coloured haloes are a visual phenomenon caused by the diffraction of light into its spectral components. This occurs when there is either **corneal edema** (fluid between epithelial cells) or **lenticular opacities**. **Why Uveitis is the correct answer:** In Uveitis, the vision is typically blurred due to inflammatory cells and "flare" in the anterior chamber. However, it does **not** typically cause the specific diffraction pattern required for coloured haloes unless secondary glaucoma develops. In fact, the presence of inflammatory debris often scatters light randomly rather than diffracting it into distinct rings. **Analysis of Incorrect Options:** * **Acute Angle-Closure Glaucoma:** This is the classic cause. Sudden, high intraocular pressure (IOP) leads to corneal edema. The edematous corneal epithelium acts as a diffraction grating, creating haloes where the blue ring is innermost and the red ring is outermost. * **Cataract (Immature Senile):** In early stages of cataract, irregular refractive indices in the crystalline lens (water clefts) cause diffraction of light, leading to "lenticular haloes." * **Pigmentary Glaucoma:** Like other forms of glaucoma with high IOP spikes, it can cause transient corneal edema and subsequent haloes. **Clinical Pearls for NEET-PG:** 1. **Fincham’s Test:** Used to differentiate Glaucomatous (corneal) haloes from Cataractous (lenticular) haloes. When a stenopeic slit is passed across the pupil, glaucomatous haloes remain intact, whereas cataractous haloes break into segments. 2. **Order of Colors:** In corneal haloes, the **Blue** ring is internal and **Red** is external (mnemonic: **B**lue is **B**efore). 3. **Other causes:** Mucus on the cornea (conjunctivitis) can also cause haloes, but these disappear after blinking or washing the eye.

Question 207: What is the cause of decreased aqueous outflow in primary open-angle glaucoma in a diabetic patient?

A. Block in episcleral veins
B. Lens
C. Block in the trabecular meshwork (Correct Answer)
D. Infection

Explanation: **Explanation:** In **Primary Open-Angle Glaucoma (POAG)**, the anterior chamber angle remains anatomically "open," but there is a functional resistance to aqueous humor drainage. The primary site of this resistance is the **trabecular meshwork (TM)**, specifically the juxtacanalicular portion. **1. Why "Block in the trabecular meshwork" is correct:** In POAG, pathological changes occur in the TM, including basement membrane thickening, loss of trabecular cells, and increased deposition of extracellular matrix (glycosaminoglycans). This creates a "clogging" effect that increases resistance to outflow, leading to elevated Intraocular Pressure (IOP). In diabetic patients, the risk of POAG is higher due to potential metabolic alterations in the TM cells, further exacerbating this blockage. **2. Why other options are incorrect:** * **Block in episcleral veins:** This occurs in conditions like Sturge-Weber syndrome or carotid-cavernous fistulas, leading to *secondary* glaucoma, not POAG. * **Lens:** The lens is the culprit in *Phacomorphic* or *Phacolytic* glaucoma (secondary angle-closure or open-angle), but not in POAG. * **Infection:** While inflammation (Uveitis) can cause secondary glaucoma, POAG is a chronic, non-inflammatory degenerative condition. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of resistance in POAG:** Juxtacanalicular trabecular meshwork. * **Risk Factors for POAG:** Age >40, Myopia, Diabetes Mellitus, Family History, and African-American race. * **Diagnosis:** Requires the triad of elevated IOP (usually >21 mmHg), characteristic optic disc cupping, and corresponding visual field defects (e.g., Bjerrum’s scotoma). * **First-line treatment:** Prostaglandin analogues (e.g., Latanoprost) which increase uveoscleral outflow.

Question 208: Painless sudden loss of vision occurs in all EXCEPT?

A. Acute angle closure glaucoma (Correct Answer)
B. Central retinal artery occlusion (CRAO)
C. Vitreous hemorrhage
D. Pseudopapillitis

Explanation: ### Explanation The key to answering this question lies in distinguishing between **painful** and **painless** causes of sudden vision loss. **1. Why Acute Angle Closure Glaucoma (AACG) is the correct answer:** AACG is a medical emergency characterized by a sudden, dramatic rise in intraocular pressure (IOP). Unlike the other options, it presents with **severe ocular pain**, headache, nausea, and vomiting. The vision loss is sudden but is accompanied by "halos around lights" due to corneal edema. Because the question asks for an exception to *painless* loss of vision, AACG is the correct choice as it is classically painful. **2. Analysis of Incorrect Options (Painless Causes):** * **Central Retinal Artery Occlusion (CRAO):** A classic cause of "amaurosis fugax" or permanent sudden, painless loss of vision. Key finding: Cherry-red spot at the macula. * **Vitreous Hemorrhage:** Causes sudden painless blurring or loss of vision, often described as "floaters" or "cobwebs" initially. Common in diabetic retinopathy or trauma. * **Pseudopapillitis:** Refers to a swollen appearance of the optic disc (e.g., in hyperopia or optic disc drusen) that is not due to increased intracranial pressure. While it usually doesn't cause sudden vision loss, when it does (as in certain ischemic variants), it is characteristically painless. **Clinical Pearls for NEET-PG:** * **Painful Sudden Loss of Vision:** Acute Angle Closure Glaucoma, Optic Neuritis (pain on eye movement), Uveitis, Corneal Ulcer. * **Painless Sudden Loss of Vision:** CRAO, CRVO, Retinal Detachment, Vitreous Hemorrhage, Ischemic Optic Neuropathy. * **AACG Triad:** Mid-dilated non-reactive pupil, stony hard eye (high IOP), and shallow anterior chamber.

Question 209: A 64-year-old woman is diagnosed with chronic simple (open angle) glaucoma. Which of the following is the most appropriate medication for this condition?

A. Brimonidine
B. Tropicamide
C. Timolol (Correct Answer)
D. Hypromellose

Explanation: **Explanation:** **Primary Open Angle Glaucoma (POAG)** is characterized by a progressive optic neuropathy with associated visual field defects, typically driven by elevated intraocular pressure (IOP). The primary goal of treatment is to lower IOP to a "target pressure" to prevent further axonal damage. **Why Timolol is the Correct Answer:** **Timolol** is a non-selective **Beta-blocker** and has historically been the first-line medical therapy for POAG (though Prostaglandin analogues are now often preferred, Timolol remains a gold-standard choice in exams). It works by **decreasing the production of aqueous humor** from the ciliary body epithelium. It is effective, well-tolerated ocularly, and administered twice daily. **Analysis of Incorrect Options:** * **A. Brimonidine:** An alpha-2 agonist. While used in glaucoma, it is generally a second-line agent due to a high incidence of follicular conjunctivitis and systemic side effects like drowsiness. * **B. Tropicamide:** A short-acting mydriatic and cycloplegic. It is **contraindicated** in patients predisposed to angle-closure glaucoma as it can precipitate an acute attack. It has no role in lowering IOP. * **D. Hypromellose:** An artificial tear substitute used for dry eye syndrome. It has no effect on intraocular pressure. **NEET-PG High-Yield Pearls:** * **Mechanism of Action:** Timolol reduces aqueous production; Latanoprost (Prostaglandin) increases uveoscleral outflow. * **Contraindications:** Avoid Timolol in patients with **Bronchial Asthma**, COPD, or heart block (due to systemic absorption via the nasolacrimal duct). * **Side Effect:** To minimize systemic absorption of Timolol, advise patients to perform **punctal occlusion** after instillation. * **Drug of Choice (DOC):** Currently, **Latanoprost** (Prostaglandin analogue) is considered the overall DOC for POAG due to superior efficacy and once-daily dosing.

Question 210: What is the most common cause of glaucoma with elevated intraocular pressure and optic nerve damage present in only one eye?

A. Sturge-Weber syndrome
B. Pseudoexfoliation syndrome
C. Blunt trauma (Correct Answer)
D. Axenfeld-Rieger syndrome

Explanation: **Explanation:** The key to this question lies in the **unilateral** presentation of glaucoma. When a patient presents with elevated intraocular pressure (IOP) and optic nerve damage in only one eye, the clinician must look for secondary causes that are localized rather than systemic or genetic. **1. Why Blunt Trauma is Correct:** Blunt trauma is the most common cause of unilateral secondary glaucoma. It leads to elevated IOP through several mechanisms: * **Acute phase:** Hyphema (blood in the anterior chamber) or inflammatory debris clogging the trabecular meshwork. * **Late phase:** **Angle recession**, where the longitudinal and circular muscles of the ciliary body tear. This leads to scarring of the trabecular meshwork months or years after the initial injury, resulting in unilateral chronic glaucoma. **2. Analysis of Incorrect Options:** * **Sturge-Weber Syndrome:** While it can cause unilateral glaucoma (due to elevated episcleral venous pressure), it is a rare neurocutaneous syndrome. Trauma is statistically much more common. * **Pseudoexfoliation (PEX) Syndrome:** PEX is a systemic condition. Although it often presents asymmetrically, it is pathologically a **bilateral** disease. * **Axenfeld-Rieger Syndrome:** This is a spectrum of **bilateral**, congenital anterior segment dysgenesis. It is hereditary (Autosomal Dominant) and typically affects both eyes. **Clinical Pearls for NEET-PG:** * **Angle Recession Glaucoma:** Suspect this in any patient with unilateral glaucoma and a history of trauma. Gonioscopy will show a "widened ciliary body band." * **10-10-10 Rule:** In trauma cases, 10% of patients with >180° of angle recession develop glaucoma 10 years later. * **Vossius Ring:** A circular ring of pigment on the anterior lens capsule is a pathognomonic sign of previous blunt trauma.

Practice by Chapter

Aqueous Humor Dynamics

Practice Questions

Primary Open-Angle Glaucoma

Practice Questions

Primary Angle-Closure Glaucoma

Practice Questions

Secondary Open-Angle Glaucomas

Practice Questions

Secondary Angle-Closure Glaucomas

Practice Questions

Developmental and Congenital Glaucomas

Practice Questions

Medical Management of Glaucoma

Practice Questions

Laser Therapy in Glaucoma

Practice Questions

Glaucoma Filtration Surgery

Practice Questions

Glaucoma Drainage Devices

Practice Questions

Angle Assessment Techniques

Practice Questions

Visual Field Testing in Glaucoma

Practice Questions

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Glaucoma — MCQs

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